This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. ABSTRACT Pirfenidone is a new experimental drug that has been found to be effective in treating a variety of fibrosing (scarring) conditions. Pirfenidone targets the same growth factors that are also present in plexiform neurofibromas. it is expected that pirfenidone will provide a means of controlling tumors inpatients with NF1. SPECIFIC AIMS Primary Objectives 1. To determine the maximum tolerated of pirfenidone administered on a chronic oral schedule (28 day cycles with no rest period between cycles) in children and young adults with neurofibromatosis type 1 (NF1) and inoperable, symptomatic plexiform neurofibromas. 2. To define the objective response rate to pirfenidone in NF1-related plexiform neurofibromas. 3. To describe and define the toxicities of pirfenidone, administered on a chronic oral schedule (28 day cycles with no rest period between cycles), in children and young adults with NF1. Secondary Objectives 1. To assess the quality of life of patients treated with pirfenidone using the National Institutes of Health (NIH) Impact of Pediatric Illness (IPI) Scale, which assesses the impact of disease and treatment on children's behavior, and to evaluate the ability of this new assessment tool to measure changes in a cihild's quality of life. 2. To assess the value of three-dimensional MRI (3-D MRI) in the evaluation of plexiform neurofibromas, and to compare 3-D MRI to conventional two-dimensional MRI (2-DMRI) and one - dimensional MRI (1-D-MRI) data analysis. 3. To contribute tumor specimens from patients who undergo tumor surgery or biopsies for clinical reasons to an already-existing tissue bank at Washington University, St. Louis, MO. Tumor specimens of plexiform neurofibromas will undergo central pathology review, including detailed morphological, ultrastructural immunohistochemical, and MRNA gene expression profile analysis. 4. To make tumor specimens that are obtained on this trial available to the scientific community, after obtaining IRB approval, in order to collect more information on the pathology, genetics, and cellbiology of plexiform neurofibromas.